Dialysis involves the movement of blood through a dialyzer that has a semi-permeable membrane. Simultaneously, dialysate is circulated through the dialyzer on an opposite side of the semi-permeable membrane. Toxins present in the blood stream of the patient pass from the blood through the membrane into the dialysate. After passing through the dialyzer, the spent dialysate is discarded. Disposal of spent dialysate requires a large amount of source water for preparing the replacement dialysate necessary for use during continuous dialysis. However, in sorbent dialysis systems, the spent dialysate is re-circulated through a sorbent cartridge rather than being discarded. The sorbent cartridge contains layers of sorbent material which selectively remove specific toxins, or break down toxins, in the dialysate.
The advantage of sorbent dialysis is that a much lower amount of water is required. In four hours of traditional dialysis, up to 120 L of water may be required to generate the dialysate. By contrast, using sorbent dialysis, as little as 6 or 7 L of water may be necessary. Thus, the need for drains and a continuous source of purified water are eliminated, rendering the system portable.
One of the drawbacks of sorbent dialysis systems is the high cost. The materials used in the sorbent cartridges can be expensive. Disposing of the cartridges after each use generates waste and drives up costs. Other known dialysate fluid circulation systems and apparatuses have separate housings where a first housing has a material capable of releasing sodium into dialysate fluid flowing through the first housing, and a second housing has a material capable of binding sodium ions from dialysate fluid flowing through the second housing. However, such systems cannot be formed into a single housing design, oftentimes require many liters of water, and may not be portable. The systems also do not provide for recharging some or all of the components of a sorbent cartridge that would allow reuse of specific components and enable lower long-term costs for operating such systems.
Hence, there is a need for a sorbent cartridge having a separation of materials within the sorbent cartridge into modules to allow for isolation of those materials. There is a need for a sorbent cartridge providing for isolation of one or more sorbent materials to allow for cheaper or non-reusable materials to be discarded, while more expensive and reusable materials are recharged. There is a further need for a unitary sorbent cartridge having multiple discreet modules that can be easily connected and/or detached from the unitary sorbent cartridge thereby facilitating the recharging and/or recycling of the sorbent materials and the sorbent cartridge while retaining a single unitary design. There is also a need for a modular sorbent cartridge having the features of reduced size and weight necessary for a portable dialysis machine. There is a need for a modular sorbent cartridge wherein the sorbent materials can be arranged within the modules of the cartridge to allow for isolation of particular materials or groups of materials. There is further a need for any one of the modules in the cartridge to be reusable or optionally detachable from the cartridge to allow any one of disposal, recycling or recharging of sorbent material within the module. There is a need for a sorbent cartridge having specific materials that can be recharged and allowing for disposal of less expensive materials.
There is a need for the sorbent materials to be recharged without removing the modules from the sorbent cartridge during operation, making the system easier to use. There is a need for a recharging means directly attached to the sorbent modules, to allow the modules to be recharged simply by directing fluid flow from the rechargers to the module. There is further a need for one or more of the modules to be removable to allow for the recycling and/or disposal of these modules, while allowing for the recharging of other modules.